Polymer compounding of graphene and related materials for advanced composite manufacturing

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Thermoplastic polymers and composites were perhaps one of the greatest material discoveries of the past century, while 3d printing is becoming the most significant manufacturing discovery of this century. Combined, they have enabled significant technological advancement in the capabilities of different products ranging from packaging to automotive to planes, and even space technology. The continued research and advancement of these technologies will impact nearly all areas of society in coming years. The most recent research into thermoplastic composites and 3d printing has come on the heels of the discovery of layered and 2-dimensional materials, such as graphene. Graphene is single sheet of graphite, which is a single atom thick with carbon atoms arranged in a hexagonal lattice. It has garnered excitement in the research and industrial community due to its outstanding mechanical, electrical, thermal, and optical properties, among others. It's application in the field of composites has already enabled the fabrication of lighter, stronger, conductive materials, capable of replacing metals and currently used composites in many high-performance systems. While graphene has shown its potential in these fields, research efforts are now aimed at moving these technologies from 'lab to fab'. This included not only the mass production of composite-ready graphene materials, but the techniques and industrial scale processes for their incorporation and integration into polymers and existing systems. This project will address each level of these considerations by investigating scale-up production techniques of graphene and layered materials and their thermoplastic composites with particular care for additive manufacturing techniques.Considering these aims, this project is investigating the scale up of graphene production using environmentally friendly processes, such as the liquid phase exfoliation of graphene in water through the use of high-pressure homogenization. This technique provides large scale production of high-quality graphene for use in composites at the ton-scale per year. The resulting material is characterized by UV-Vis spectroscopy, Raman spectroscopy, atomic force microscopy, and scanning electron microscopy. Next, the produced materials are incorporated into polymers through several available processes, such as extrusion to produce pellets or 3d printing filaments, or through high shear incorporation in the high-pressure homogenizer with powdered polymers. The resulting composites are analysed using thermogravimetric analysis, differential scanning calorimetry, and laser flash analysis for the thermal properties, while tensile testing is used for mechanical characterization. The final step in moving these technologies to industry requires the demonstration of fabrication techniques. The composite materials are then compression molded, 3d printed, and injection molded, demonstrating the viable routes to industry for graphene-based materials from material synthesis to final device fabrication.